Optical networks are employed to support the demand for high-speed, high-capacity advanced telecommunications and data networks. These optical networks commonly utilize optical dense wavelength division multiplexing (DWDM) to exploit the available optical spectrum. In optical DWDM, data is modulated onto several different carrier waves of different wavelengths. The modulated carriers are commonly referred to as wavelength channels. The optical frequency slots in which the wavelength channels propagate are termed wavelength channel slots.
Many optical networks employ optical nodes that correspond to branch points of the optical network. Often, these nodes employ Reconfigurable Optical Add Drop Multiplexer (ROADM) devices that allow for the removal or addition of one or more channel wavelength slots at a node. Optical networks also include optical amplifiers between the ROADM devices to amplify the signal during transmission. A common example of an optical amplifier is an Erbium Doped Fiber Amplifier (EDFA).
In DWDM systems, adding and deleting signals on wavelength channel slots causes power changes to other wavelength channels, due to transient and steady state amplification effects of the EDFAs, and fiber Stimulated Raman Scattering (SRS) effect. In order to limit power changes related to these transient and steady state behaviors, the number of signals on channels to be added or deleted, or both, at a given time is typically kept small and channel power optimization may be used. Limiting the number of signals on channels that can be added or removed at a given time and performing channel power optimization can result in the channel slot add/delete process being slow.